Cell Structure and Functions — Science STD 8 — Question

Saniya claims to her friend Vinita that “Antibiotics can cure any infection, so we don’t need to worry about diseases.” What question(s) can Vinita ask her to help Saniya understand that her statement is incorrect?

In year 2013, there was a showcase in IIT Hyderabad. All the students from different schools and colleges were invited on that occasion. Naveen with his friends went to see the projects made by M.Tech students. He found a project based on the construction of anti-earthquake buildings in which the small houses of iron rods were constructed. One house was with a hose containing water and the other was without hose. They were shocked on shaking of both the houses.
(i) Describe an earthquake.
(ii) Explain the meaning of quake-resist building.
(iii) Mention which force reduces the shaking in a building with hose.
(iv) State the feeling about the students who showed their project.

What is meant by water pollution? What are the different ways in which water gets polluted?

What is meant by atmospheric pressure? What is the cause of atmospheric pressure?

Who is responsible for the sex of the unborn child: father or mother? Why?

With the help of a labelled diagram, describe briefly how an iron key can be electroplated with copper.

Explain why, thermoplastics become soft on heating but thermosetting plastics do not become soft on heating. Draw labelled diagrams to illustrate your answer.

Give an example to show that friction depends on the force with which the two surfaces are pressed together.